Adhesive tape dispensers



y 23, 1970 H; STEPHENS ETAL 3,521,800

ADHESIVE TAPE DISPENSERS Filed April 10, 1967 mvawron s United States Patent 3,521,800 ADHESIVE TAPE DISPENSERS Hugh Stephens, 90 Leighton Ave., Winnipeg 15, Manitoba, Canada, and Robert M. Stephens, 296 Matheson Ave., Winnipeg 4, Manitoba, Canada Filed Apr. 10, 1967, Ser. No. 629,678 Int. Cl. B2615 3/02 US. Cl. 22521 2 Claims ABSTRACT OF THE DISCLOSURE Applicants employ a degree of flexion in a tape rest medially positioned between the roll and the cutter bar of a tape dispenser with the object of ensuring under all conditions the separation of the tape from the cutter bar following severance. The bending of the tape rest is limited by a stop which permits a higher tension to be put on the tape. The tape rest in question forms part of Pat. No. 3,265,264 and has a concave upper face. Present application places an upper and lower limit on this concavity.

CROSS REFERENCE TO RELATED APPLICATIONS This application should be read against US. Pat. No. 3,265,264 dated Aug. 9, 1966, granted to Hugh Stephens and related to improvements in adhesive tape dispensers to which attention is directed and in which the function ing of certain improvements were thoroughly expounded The subject matter of present improvement is confined t0 the inclusion of limited flexion in the tape rest previously described in the above patent and to define the upper and lower limits of the concavity of the face of the tape rest.

BACKGROUND OF THE ART The above-mentioned patent describes the deficiencies in dispensers currently marketed, briefly outlined as (a) a roll back of the tape following severance (b) the need to provide a free end of tape following severance (c) adherence of the severed end to the cutter bar These problems were solved by (a) interpositioning a tape rest medially between the roll and the cutter bar to prevent roll-back and at the same time provide a length of tape beyond the tape rest; (b) designing the rest face with a concavity to provide a curved rigidity to the tape and assure its forward projection following severance; (c) said concavity creating a stress differential in the tape as it was stretched prior to severance causing the tape to withdraw from the cutting edge following severance.

It has been further noted by experiment that to secure the latter action there were limits to the amount of concavity that could be applied. If the perpendicular height of the arc in relation to the chord was less than 7 percent, the necessary degree of rigidity following severance was not obtained and if the ratio exceeded 12 percent, the tape was unable to conform to the curvature :of the tape rest. However it has been observed there is a considerable variation both in the thickness, affecting strength, and in the tackiness of tapes, and since these tapes are sold as refills by different manufacturers with differing standards it is essential that dispensers be constructed capable of dealing with all variations in a manner satisfactory to the user.

While tapes of standard thickness and ordinary tackiness are severed and the free end caused to project forward in the manner outlined in the patent mentioned above, instead of dropping, the tendency of thinner tapes as well as the inordinately tackier ones to adhere to the 3,521,800 Patented July 28, 1970 ice SUMMARY OF THE INVENTION Applicants have constructed a dispenser having a tape rest capable of flexing in the direction of the cutter bar, a stop to limit the degree of flexion, and having upper and lower limitations to the degree of concavity in the face of the rest.

Since the designed concavity of the tape rest in Pat. No. 3,265,264 ensures that the tape adheres to it in every instance and that the free end of the tape assumes the curvature of the concavity, only a small amount of flexion in the tape rest is needed to withdraw such thinner and inordinately tackier tapes off the cutting edge following severance. However it is essential that the flexible tape rest be possessed of sufficient resistance to generate in the tape, when stretched, the necessary stress differential across the face of the tape at the moment prior to its severance. This is achieved by an inward protrusion of the side walls of the frame to form a rest stop.

In the drawings FIG. 1 is a right side elevation. FIG. 2 is a front elevation. FIG. 3 is a fragmentary interior view of the dispenser frame showing the tape rest insert and the degree of flexion. FIG. 4 is an isometric view of dispenser and tape rest.

A tape roll 2 is axially mounted at 3 within container 1. The tape rest 6 is inserted within guides 11 and adhesively secured thereto forming an integral part of container 1. Interposed on the inner side walls of frame 1 are protrusions 12 formed to provide a stop for the flexible rest 6.

In operation the free end of tape 10 is pulled from the roll 2 passing over the tape rest leading edge 8 and beyond trailing edge 9. As the tape 10 is lowered towards cutter bar 4 the tape adheres first to leading edge 8 then the trailing edge 9, conforming to the concavity 7 of the tape rest 6, thus providing sufficient anchorage as the tape 10 is pulled against the flexibility of the upright portion of the tape rest 6. Further tension on the tape 10 draws the tape rest 6 forward until it reaches stop position 12. Continued tension creates a stress differential in the tapes surface caused by the concavity 7 as the tape 10 is pulled over cutter bar 4. Following severance at the cutting edge 5 the reflex action of the upright portion of the tape rest 6 as it returns from stop position 12 to its original position frees the tape 10 from the cutting edge 5. The curvature assumed by the free end of the tape 10 in responding to the concavity 7 of the tape rest 6 following severance assures its forward projection, and the medial positioning of the rest 6 provides a free end of ample length sufficient to permit it to be grasped readily. A tape rest of the insert type is preferred since it facilitates the molding process and enables a support frame to be made of a more rigid material supplemented by the flexible tape rest. While a tape rest of flexible plastic is preferred the use of a spring steel rest is not precluded should this be found practical.

The purpose has been to create a tape dispenser that is economical to manufacture, durable, serviceable, devoid of complexity and designed to avoid all the imperfections the present commercial articles possess.

We claim:

1. Improvements in adhesive tape dispensers of the type comprising a roll of adhesive tape (2) rotatably mounted within a frame (1), a cutter bar (4) distant from said roll of. tape (2) forming part of said frame (1), a tape rest (6) transversely disposed within said frame 1) and medially positioned between said roll of tape (2) and said cutter bar (4), the upper face (7) of said tape rest (6) being flat in line of and concave transverse of the tape flow between the roll (2) and the cutter bar (4) said tape rest having a leading edge (8) and a trailing edge (9) intercepting in ordered sequence said line of tape fiow between the point of tape disengagement from the roll (2) and the cutting edge (5) of said cutter bar (4), wherein said improvement consists in said frame (1) being of composite construction having oppositely disposed vertical guides (11) on the interfaces of the sidewalls of said frame (1), said tape rest (6) insertably receivable by said guides (11), said frame (1) having inward protrusions of its sidewalls at a point forwardly 10 fined in claim 1 consisting in the arc of concavity of face (7) of the tape rest (6) having a ratio of perpendicular height to chord of not less than 7 percent and not more than 12 percent.

References Cited UNITED STATES PATENTS 2,264,425 12/1941 Witter 22521 2,506,504 5/1950 Hudson 225-21 3,265,264 8/1966 Stephens 22S--25 JAMES M. MEISTER, Primary Examiner US. Cl. X.R. 

